The only quality issue I've noticed is a very quick stutter that occurs, maybe, once a minute. I don't believe it has anything to do with my connection as when I call my number using a POTS line and go into voicemail, I noticed the same stutter with the woman's voice on the outgoing message.

Other than that, the quality seems excellent! I even used the TellMe, voice-response service, mumbled my words, and it never skipped a beat!